US 5,519,319 AGranted

Obtaining measurements of improved accuracy of one or more polymer properties with an on-line NMR system

AssigneeAuburn International, Inc.

InventorsThomas B. Smith, Scott A. Marino, Ronald J. Tache, David R. Day, Christian I. Tanzer, Tadd B. Hughes, Ajoy K. Roy

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Abstract

A nuclear magnetic resonance (NMR) system, and related method, develops two or more regression equations or models for a particular polymer property of interest (e.g., melt index or MI) during a calibration procedure using known samples of a material. The polymer material can be, for example, a plastic (e.g., polyethylene, polypropylene, or polystyrene) or a rubber (e.g., ethylene propylene rubber). Regression models for one or more discrete (i.e., two-valued) variables also are developed during calibration, and these models allow a prediction to be made about which of the two or more property (e.g., MI) models should be used for any particular sample of unknown material. The prediction obtained from the discrete variable model indicates which of the two or more models will produce the most accurate estimation of the property of interest for the unknown sample. The best model is thus selected, and then it is used to estimate the property of interest.

Claims12

Dependent claims

A method for measuring polymer properties of samples in real time, comprising:

storing a plurality of models wherein at least two of the models are useful in predicting a value of a particular property of a sample and at least one of the models is useful in identifying which of the at least two models more accurately predicts the value of the particular property;
taking a series of samples of an unknown polymer material from an industrial on-line process and placing each of the samples successively in a test region;
applying a base magnetic field to the sample in the test region to effect precession of nuclei of the sample;
modifying the precession;
receiving a resulting relaxation signal representative of a free induction decay of the nuclei of the sample;
digitizing the free induction decay and analyzing it into component equations;
processing the component equations with an iterative technique to derive coefficients representative of the component equations;
utilizing the coefficients, or information based on the coefficients, and the at least one model in order to select one of the at least two models;
utilizing the coefficients, or information based on the coefficients, and the selected one of the at least two models in order to predict the value of the particular property;
and
discarding the sample from the test region.

8 more elements

Apparatus for measuring polymer properties of samples in real time, comprising:

means for storing a plurality of models wherein at least two of the models are useful in predicting a value of a particular property of a sample and at least one of the models is useful in identifying which of the at least two models more accurately predicts the value of the particular property;
means for taking a series of samples of an unknown polymer material from an industrial on-line process and placing each of the samples successively in a test region;
means for applying a base magnetic field to the sample in the test region to effect precession of nuclei of the sample;
means for modifying the precession;
means for receiving a resulting relaxation signal representative of a free induction decay of the nuclei of the sample;
means for digitizing the free induction decay and analyzing it into component equations;
means for processing the component equations with an iterative technique to derive coefficients representative of the component equations;
means for utilizing the coefficients, or information based on the coefficients, and the at least one model in order to select one of the at least two models;
means for utilizing the coefficients, or information based on the coefficients, and the selected one of the at least two models in order to predict the value of the particular property;
and
means for discarding the sample from the test region.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/491,632Filed 19 Jun 1995 · continuation in part
Priority: 20 Nov 1991
Granted: 21 May 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01R 33/389
Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field: field stabilisation , e.g. by field measurements…
G01N 24/085
By using nuclear magnetic resonance: analysis of materials for the purpose of controlling industrial production systems
G01N 24/082
By using nuclear magnetic resonance: measurement of solid, liquid or gas content
G01R 33/4625
NMR spectroscopy: processing of acquired signals, e.g. elimination of phase errors, baseline fitting, chemometric analysis

Family

Serial794,931Parent of this continuation · filed 20 Nov 1991
Serial885,633Parent of this continuation · filed 19 May 1992
Serial226,024Parent of this continuation-in-part · filed 11 Apr 1994
Serial226,061Parent of this continuation-in-part · filed 11 Apr 1994
US 5,302,897 AParent of this continuation · filed 12 Apr 1994
US 5,302,896 AParent of this continuation · filed 12 Apr 1994
Serial370,862Parent of this continuation-in-part · filed 10 Jan 1995
Serial371,091Parent of this continuation-in-part · filed 10 Jan 1995
US 5,519,319 AThis patent

From the US filing history. Foreign family members aren’t listed.